16644899405 has 4 divisors (see below), whose sum is σ = 19973879292. Its totient is φ = 13315919520.

The previous prime is 16644899399. The next prime is 16644899419. The reversal of 16644899405 is 50499844661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8802380041 + 7842519364 = 93821^2 + 88558^2 .

It is not a de Polignac number, because 16644899405 - 2²⁰ = 16643850829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1664489936 + ... + 1664489945.

It is an arithmetic number, because the mean of its divisors is an integer number (4993469823).

Almost surely, 2^16644899405 is an apocalyptic number.

It is an amenable number.

16644899405 is a deficient number, since it is larger than the sum of its proper divisors (3328979887).

16644899405 is an equidigital number, since it uses as much as digits as its factorization.

16644899405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3328979886.

The product of its (nonzero) digits is 7464960, while the sum is 56.

The spelling of 16644899405 in words is "sixteen billion, six hundred forty-four million, eight hundred ninety-nine thousand, four hundred five".